Convertible Senior Notes ("Notes"), Note Hedges, and Warrants - Additional Information (Detail) - USD ($)	9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Debt Instrument [Line Items]
Net carrying amount	$ 293,516,000		$ 284,818,000
Aggregate amount paid for Note Hedges		$ 63,928,000
Proceeds from sale of warrants		$ 34,535,000
Liability Component [Member]
Debt Instrument [Line Items]
Net carrying amount	293,516,000		284,818,000
Equity Component [Member]
Debt Instrument [Line Items]
Debt issuance costs	1,582,000		1,582,000
Net carrying amount	62,061,000		62,061,000
Equity Component Gross Value [Member]
Debt Instrument [Line Items]
Net carrying amount	63,643,000		$ 63,643,000
0.75% Convertible Senior Notes Due 2019 [Member]
Debt Instrument [Line Items]
Debt instrument, principal amount	$ 345,000,000
Interest rate of debt, stated percentage	0.75%
Debt instrument, maturity year	2019
Net proceeds from issuance of debt	$ 336,400,000
Net proceeds used to pay cost of Note Hedges	$ 29,400,000
Debt instrument, description	The Notes are senior unsecured obligations of EFI with interest payable semiannually in arrears on March 1 and September 1 of each year, commencing March 1, 2015. The Notes are not callable and will mature on September 1, 2019, unless previously purchased or converted in accordance with their terms prior to such date.
Conversion rate, number of share per $1,000 principal amount	18.9667
Conversion rate, principal amount of Notes	$ 1,000
Initial conversion price	$ 52.72
Debt instrument, Conversion rate description	• during any calendar quarter commencing after the calendar quarter ending on December 31, 2014 (and only during such calendar quarter), if the last reported sale price of our common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day; • during the five business day period after any five consecutive trading day period (“Notes Measurement Period”) in which the “trading price” (as the term is defined in the Indenture) per $1,000 principal amount of Notes for each trading day of such Notes Measurement Period was less than 98% of the product of the last reported stock price on such trading day and the conversion rate on each such trading day; • upon the occurrence of specified corporate events; or • at any time on or after March 1, 2019 until the close of business on the second scheduled trading day immediately preceding the maturity date.
Conversion threshold minimum stock price as a percentage of conversion price	130.00%
Effective interest rate percentage	4.98%
Deferred tax liability	$ 23,700,000
Common stock strike price per share	$ 68.86
0.75% Convertible Senior Notes Due 2019 [Member] | Debt Issuance Costs [Member]
Debt Instrument [Line Items]
Effective interest rate percentage	5.46%
0.75% Convertible Senior Notes Due 2019 [Member] | Liability Component [Member]
Debt Instrument [Line Items]
Debt issuance costs	$ 7,000,000
0.75% Convertible Senior Notes Due 2019 [Member] | Equity Component [Member]
Debt Instrument [Line Items]
Debt issuance costs	$ 1,600,000